Counting system



Jan. 22, 1952 W, H, T, HOLDEN COUNTING SYSTEM Filed July 24. 1950 w W WSTW A A A /NVENTOR W H. 7. HOLDEN .9v

A r Tom/Ev Patented Jan. 22V, 1952 UNIT 151D.Y STATES TENT- oler-Ice to.Bell-Telephone Laboratories, Incorporated, New York, N; Y., avcorporation of NewYork l 151'Clairns.

This intenti@ relates. t9 @Hitting Systemeefid leere Dertieulaltlv'teeireuite fer eutrie, eleettieelruleee A11 Objeet. Qt, this itletltieriis the` eeeulete counting of. electrical'p mena recurring( athighratesof speed, t

i feature of this invention is; aA bidirectional counter operable te@Cunt i.1'f1 eitrv ef tti/,0 di-v teetierey i-jef,either` te tenet. erteuneeurit: either te ed@ er Subetreet.

Another featurei ef this.4 intention. ie. the Se f uneireetieeel.eilrlrent. eelduetre. devices es' entitle, meterteY with meeref 'forexternally e011- trolling the eilective: impedance o; the gatesftopulses, applied therete- The manner Vin which, the object is attainedand 'a more eemrlete., understanding ef the 'listed and: other. featuresof` thel invention r'nay be ob?` tained. from the.. fpllewin'g' detaileddeeeriritien ef, nrefetred. embedmente ef. theLinventen'Weet-l read withreferenceV to thev accompanying drawmgsrn which;

Fig. k1 is acircuit diagram ofonevfvorin of the. invention, utilizingCQld, cathode easeoiis'y diseheree. devices: and

Fig. 2 is a circuit diagram of another form ot the invention utilizinghet Cathode. aseeln discharge devicesfor. thyratrons. 'Y

Let the fundamental principles governing the design` of a bidirectionalor addfsubtract binary :r

counting circuit first be considered. Every integer on a decimaibasismay be represented as the summation of discrete powers of the digit 2.vThus, as is demonstrated in; the following table, the decimal integer 1may be represented as thel zero power of the digital base 2A; thedecimal` integer 5 may be represented as the summation of the second andthe zero.l powers of the digital base. 2 ;y the decirnalinteger 1 5 ,maybe :representedV as 23+2`2|21+2L and Solon.

BinaryNui-nber Decimal Number In a binarycounter, n stages arenor-xnaiklyprovided- With'the condition of the successive stages ibeiriereereeeetatre et the presenteer ebseneeef the, eileeee'eive;Peters 0Min theinteeer. tenete/d., it e.,' 20,21. 22". 2?( Further; eachstage of Aa binary counter isno call in either onefo'r theV @einenumeral 1. neither; eene@ to er subtract# frogfnh'the pri rvregistration.' the rst er unite et ZFSte'ee' et theeeuiiter, feest'always shiftlV its state VWheneveigf a` pulseis applied to the Systemwhethettie operation, be'edtiten er! Sbtmnionn--. Y Y, v

liveettefietine. the. Second er te er 2.1 Stege ofn the counter; inthefprocessbf addition: "It the 2 1 stage. loemoff or at O andthe firstor 20. stage Aon o r "at 1,- a received pulse must devanc the ze stagetqfo andthe 21 stage tdi.

Similarly. the211fstage be on" or at 1 and the. Iirst ork 2.0 stagefalsobe 1, aV received pulse iniist advance the '2 9' stage to` 0V and the21, stage te4 Q also An iust change thestate of the third or 2? stage'.1i thefz? stage were previously at 1 thisf pulse rnust also shiftvthev23 stage, and. if die "ze Stege 'were else; at 1 sp that the shift is to0 the 2j? stagemust* also be shifted, Vand so cn. Obviously, in theprocess of addition, if

t the first or. 'unitsstage be at 0, only the state eilthetlfst. etageheed be shifted 1n the. process of subtraction: If the units or 2,stage'is on 1 when al pulse is received,\only the state of that stage need b'e shifted. 1f*` the units or 2 stage her on 0, Vthen the pulse4must also shift the state of the' 2,1 stage, and if that st gewaspreviously on 0 Vvvhereloy vthis pulsev shifts itto th'ef'lV state, thenthe state of the next si. `eeeetrie er'Z Stege. met ette be .shifted endso on.

` "Defviee e.. general, preposition. from. the abete considerations, 'inthe 'process of' addition, the th'wcunter (which counts the nth power ef2) triest elve'eeefetti state, 0 testate 1 Wheeever the v1'i-"1 'counteradvances from state 1 toV state 0, loutl the Anth s'tagmshould benon-resiponsiv'e to "a shirt fthe n-r-'l stage from'the.

O state to vthe h1 state. "In ythe process of Sub-f traction, ythenthcounter rust inove from state() to state 1 whenever "thend counter movesfrom state 0 to statev 1, and must also cause'th'e next succeeding orn+1 stage to shift its state. When the' `r'-1" etet'ef metes trete etete0 to state l with the nthk stagemat'state 1, they f'nth stage mustinove'fristate `1 to stateI O'in the process of subtraction, but no enectshould be produced in the nth or higher stages.

'I'he design of a bidirectional binary counter may be predicated on theabove-developed propositions. It will be seen that the iirst or 2 stagemay be driven directly from the pulse source since its state must bereversed at each pulse. Two output paths are provided coupling the rstor 2 stage to the next or 21 stage. A pulse is transmitted over one ofthese paths when the rst or 2 stage advances from its 0 to its 1 state,and a pulse is transmitted over the other of these paths when the rst or2 stage passes from its 1 to its 0 state. Two control conductors areprovided with the potentials on those conductors being selected inaccordance with whether addition or subtraction is to be performed.Gates controlled by the voltages impressed on these two controlconductors determine which of the two pulses transmitted from the stageis applied to the next or 21 stage. All higher stages are similarlyequipped with dual outputs, with a gate individual to each of theoutputs and with the condition of the gates being controlled by thevoltages on the control conductors.

Referring now to Fig. l of the drawings, three stages of a bidirectionalbinary counting system are represented, designated, respectively, n-l,n, and n+1. Each stage comprises a trigger circuit having two stablestates. In the embodiment of the invention shown in Fig. 1, each triggercircuit comprises a pair of cold cathode gaseous discharge devices whichmay, for example, be of the type designated WE 376-3 or RCA 5823. Eachtube is provided with an anode, a cathode, and a start electrode, e. g.,tube |0| in stage n-1 is provided with an anode I 01, a cathode |08, anda start electrode |09. The anodes of all of the tubes are connected viaconductor ||0 to a positive source of potential Ebb which may provide,for example, 135 volts. The cathode of each tube is connected to ground(negative Ebb) through an individual resistor. Thus, the cathode |08 oftube |0| is grounded through resistor IH and the cathode of tube |02 isgrounded through resistor I2. The cathodes of the two tubes comprisingeach trigger circuit are interconnected by a capacitor, e. g., thecathodes of tubes |0| and |02 are interconnected by capacitor ||3.

Considering now, for example, the n-l stage comprising tubes |0| and|02, let it be assumed that one of the tubes of the trigger pair. suchas the 0 tube |0|, is conducting while the other tube in the triggerpair, such as the 1 tube |02 is extinguished. The anodes of both tubeswill obviously remain at the plate supply voltage Ebb, viz., 135 volts,and the cathode of the non-conducting tube |02 will be stabilized atapproximately ground potential. The cathode of the conducting tube 0|,however, will rise to a value less thanthe supply voltage Ebb by anamount equal to the main gap sustaining voltage of the tube, i. e.,Ebb-Es. In the above-noted type of tube, Es is typically in the vicinityof 70 volts so that the cathode of the conducting tube will rise to135-'70 or 65 volts positive relative to ground. This potential must beless than the start-gap breakdown voltage of the tubes for a reasonhereinafter to be noted and the value of Ebb may be adjusted so toprovide. It will herein be assumed that the start-gap breakdown voltageof the tubes is in the vicinity of 100 volts.

It will be seen that as a result of the trigger circuit comprising tubes|0| and |02 being in this stable state, i. e., the 0 state, capacitor||3 Gil 4 will assume a charge of approximately volts, with theleft-hand electrode of capacitor ||3 being approximately 65 voltspositive relative to the right-hand electrode thereof.

If a positive pulse of suitable amplitude be impressed on the startelectrodes of both of these tubes in a manner hereinafter to bediscussed, the pulse will have little or no eiect on the presentlyconducting 0 tube |0|, but it will initiate a discharge in the presentlynon-conducting ltube |02 between the start electrode and the cathodethereof. This discharge, by the nature of the tube and the appliedvoltages, will immediately transfer so as to exist between the mainanode and the cathode. As a result, the cathode of tube |02 willimmediately rise to a potential Ebb-Es or 65 volts positive. Sincecapacitor ||3 has already been charged to Ebb-Es or 65 volts positive asabove described,

l the left-hand electrode of capacitor ||3, and

consequently the cathode |08 of tube |0|, will attain transiently apotential of 2(Ebb-Es) or volts positive relative to ground. Therefore,during this transient period, the cathode of the previouslynon-conducting tube |02 will rise to 65 volts positive and the cathodeoi the previously conducting tube will rise to 130 volts positive. Thesepotentials are employed in controlling the state of the next succeedingstage in a manner hereinafter to be described.

During the transient condition, thecathode of tube, |0| risesmomentarily to approximately 130 volts positive relative to ground asabove noted. lSince the anode of tube |0| is at positive volts, thepotential diiference across this main gap is considerably below thesustaining voltage of the tube, and tube |0| will be extinguishedwhereby the n-l stage will rest in its 1" stable state.

The cathodes of each tube in each stage are coupled to the startelectrodes of the tubes in the next succeeding stage. Thus, the cathode|08 of tube |0| is connected through resistors ||4 and ||5, varstor H0,through resistor ||'|1 to the start electrode of tube |03 and throughresistor ||8 to the start electrode of tube |04. Similarly, the cathodeof tube |02 is connected through resistors |20 and |2|, varistor |22,through resistor lil to the start electrode of tube |03 and throughresistor H8 to the start electrode of tube |04. The varistorsrepresented in the drawings are unidirectional current conductingdevices and may comprise conventional dry rectiers, gas diodes, etc. Thevaristors are'represented as having a low impedance to conventionalcurrent flow in the directionsof the arrow when the arrow sides thereofare at a potential positive relative to the other sides.

'Iwo control leads are provided. They are designated, respectively, theadd lead |25 and the "subtract lead |26. At a point intermediate the tworesistors H4 and H, the circuit coupling the cathode of tube |0| to thestart electrodes of the tubes in the next stage is connected to thesubtract lead |26 by means or a varistor |28. Similarly, at a pointintermediate the two resistors |20 and |2|, the circuit coupling thecathode of tube |02 to the start electrodes of the tubes in the nextstage is connected to the add lead |25 by means of a varistor |29. Itwill be noted that the varistors or gates |28 and |29 are poled withtheir arrows directed towards the control conductors.

Selected potentials are applied to the control The speed capabilities oithe disclosed counting circuit may be increased by the use of thyratronsor hot cathode gaseous discharge devices rather than the cold cathodegaseous discharge devices shown in Fig. 1. Fig. 2 demonstrates thi-smodiilcation. The circuits of Figs. 1 and 2 are substantiallyoperationally identical, the only modifications in the circuitry of Fig.2 being those necessary to compensate for the different voltagerequirements of the thyratron. Thus, for example, the cathodes of tubesand 202 are grounded through resistors 2|| and 2|2, respectively, andthe anodes of all of the tubes are con nected to a source of positivepotential Ebb which, in this case, may have a wider latitude, e. g.,from 135 to 250 volts. Only a part of the pulse across the cathoderesistors 2|| and 2|2 need be used since the rise in cathode potentialwhen one of the thyratrons 20| to 206 is discharged is large, thesustaining voltage Es of a thyratron being normally in the range ofapproximately 7 to 20 volts so that Ebb-Es closely approaches Ebb.Therefore, the networks coupling any stage to the next succeeding stageare tapped to a point on the cathode resistors rather than directly tothe cathodes. Additionally, by the nature of the thyratron, the gridsmust be biased negatively relative to the cathodes to preventconduction. Thus, the grids of tubes 203 and 204 are connected throughindividual resistors 2|? and 2l3 and through common resistor 240 tonegative battery which may supply, for example, negative volts.

Similarly, because of the differences between the characteristics ofcold cathode triodes and thyratrons, the voltage supplied through theNo. 3 contact of switch SW2 to the subtract lead 226 during the processof addition and through the No. 2 contact of switch SW2 to the add lead225 during the process of subtraction is approximately 50 voltsnegative. The voltage supplied through the No. 1 contact of switch SW2to the add lead 225 during the process of addition and through the No. 4contact of switch SW2 to the subtract lead 226 during the process ofsubtraction is approximately 10 volts positive as obtained from thevoltage ,divider 24|.

Considering these differences in applied voltages, the operation of thecircuit of Fig. 2 is the same as the operation of the circuit of Fig. 1,

above described in detail, and the reference characters referring to thecorresponding elements in the two figures have corresponding tens andunits digits.

It is to be understood that the above-described arrangements are butillustrative of the application of the principles of thev invention.Numerous other arrangements may be devised by those skilled in the artwithout departing from the spirit and scope of the invention.

What is claimed is:

1. In a counting circuit, two control conductors, a plurality of stages,rst and second means interconnecting adjacent ones of said stages, aunidirectional current conducting device connecting said rst means toone of said control conductors, and another unidirectional currentconducting device connecting said second means to the other of saidcontrol conductors.

2. In a counting circuit, a plurality of trigger circuits, meansinterconnecting adjacent ones of said trigger circuits, an add lead, asubtract lead, and unidirectional current conducting means connectingsaid means to said add lead and to said subtract lead. A

3. In a, counting circuit, a plurality of trigger circuits, an add lead,a subtract lead, first and second means interconnecting adjacent ones ofsaid trigger circuits, a unidirectional current conducting deviceconnecting said rst means to said add lead, and another unidirectionalcurrent conducting .device connecting said second means to said subtractlead.

4. In a counting circuit, a plurality of pairs of electron dischargedevices, rst means connecting one of the devices in each of the pairs tothe next succeeding one of said pairs of devices, second meansconnecting the other one of the devices in each of the pairs to the nextsucceeding one of said pairs of devices, two control conductors,unidirectional current conducting means connecting said iirst means toone of said control conductors, and unidirectional current conductingmeans connecting said second means to the other of said controlconductors.

5. In a counting circuit, a plurality of pairs of electron dischargedevices, each of said devices having at least a cathode and a startelectrode, rst means connecting the cathode of one of the devices ineach of the pairs to the start electrodes in the next succeeding pair ofdevices, second means connecting the cathode of the other of the devicesin each of the pairs to the start electrodes in the next succeeding pairof devices, two control conductors, unidirectional current conductingmeans connecting said first means to one of said conductors, andunidirectional current conducting means connecting said second means tothe other of said conductors.

6. In a counting circuit, a plurality of pairs of electron dischargedevices, each of said devices having at least a cathode and a startelectrode, a capacitor interconnecting the cathodes of the devices ineach of said pairs of devices, rst means connecting the cathode of oneof the devices in each of the pairs to the start electrodes in the nextsucceeding pair of devices, second means connecting the cathode of theother of the devices in each of the pairs to the start electrodes in thenext succeeding pair of devices, two control conductors, unidirectionalcurrent conducting means connecting said rst means to one of saidconductors, and unidirectional current conducting means connecting saidsecond means to the other of said conductors.

7. In a counting circuit, two control conductors, a plurality of stages,means including unidirectional current conducting means interconnectingadjacent ones of said stages, and unidirectional current conductingmeans connecting said means to said control conductors.

8. In a counting circuit, two control conductors, a plurality of stages,iirst and second means including unidirectional current conducting meansinterconnecting adjacent ones of said stages, a unidirectional currentconducting device connecting said iirst means to one of said controlconductors, and another unidirectional current conducting deviceconnecting said second means to the other of said control conductors.

9. In a counting circuit, a plurality of pairs of electron dischargedevices, first means including unidirectional current conducting meansconnecting one of the devices in each of the pairs to the nextsucceeding one of said pairs of devices, second means includingunidirectional cur rent conducting means connecting the other one of thedevices in each of the pairs to the next succeeding one of the saidpairs of devices, two control conductors, unidirectional current con-`including unidirectional ducting means connecting said rst means to oneof said control conductors, and unidirectional current conducting meansconnecting said second means to the other of said control conductors.

1G. In a counting circuit, a plurality ci pairs of electron dischargedevices, iirst means including two resistors and unidirectional currentconducting means connecting one of the devices in each of the pairs tothe next succeeding one of said pairs of devices, second means includingtwo resistors and unidirectional current conducting means connecting theother one of the devices in each of the pairs to the next succeeding oneof said pairs or" devices, two control conductors, unidirectionalcurrent conducting means connecting said rst means at a pointintermediate said two resistors to one of said control conductors, andunidirectional current conducting means connecting said second means ata point intermediate said two resistors to the other of said controlconductors.

1l. In a counting circuit, a plurality of pairs of electron dischargedevices each having at least a cathode, a capacitor interconnecting thecathodes of the devices in each of said pairs of devices, rst meansincluding unidirectional current conducting means connecting one of thedevices in each of the pairs to the next succeeding one of said pairs ofdevices, second means current conducting means connecting the other oneof the devices in each of the pairs to the next succeeding one of saidpairs of devices, two control conductors, unidirectional currentconducting means connecting said first means to one of said controlconductors, and unidirectional current conductingmeans connecting saidsecond means to the other of said control conductors.

12. In a counting circuit, a plurality of pairs of electron dischargedevices, each of said devices having at least a cathode and a startelectrode, rst means including unidirectional current conducting meansconnecting the cathode of one of the devices in each of the pairs to thestart electrodes in the next succeeding pair of devices, second meansincluding unidirectional current conducting means connecting the cathodeof the other of the devices in each of the pairs to the start electrodesin the next succeeding pair of devices, two control conductorslunidirectional current conducting means connecting said rst means to oneof said conductors, and unidirectional current conducting meansconnecting said second means to the other of said conductors.

13. In a counting circuit, a plurality of pairs of electron dischargedevices, each of said devices having at least a, cathode and a startelectrode, first means including two resistors and unidirectionalcurrent conducting means connecting the cathode of one of the devices ineach of the pairs to the start electrodes in the next succeed -ing pairof devices, second means including two resistors and unidirectionalcurrent conducting means connecting the cathode of the other of thedevices in each of the pairs to the start electrodes in the nextsucceeding pair of devices, two control conductors, unidirectionalcurrent conducting means connecting said iirst means at a pointintermediate said two resistors to one of said conductors, andunidirectional cur rent conducting means connecting said second means ata point intermediate said two resistors to the other of said conductors.

14. In a counting circuit, a plurality oi pairs of electron dischargedevices, each of said devices having at least a cathode and a startelectrode, a capacitor interconnecting the cathodes of the devices ineach of said pairs of devices, first means including unidirectionalcurrent conducting means connecting the cathode of one oi the devices in,each of the pairs to the start electrodes in the next succeeding pairof devices, second means including unidirectional current conductingmeans connecting the cathode of the other of the devices in each oi thepairs to the start electrodes in the next succeeding pair of devices,two control conductors, unidirectional current conducting meansconnecting said iirst means to one of said conductors, andunidirectional current conducting means connecting said second neans tothe other of said conductors.

15. In a counting circuit, a plurality of pairs of electron dischargedevices, each of said devices having at least a cathode and a startelectrode, a capacitor interconnecting the cathodes of the devices ineach of said pairs of devices, nrst means including two resistors andunidirectional current conducting means connecting the cathode of one ofthe devices in each of the pairs of the start electrodes in the nextsucceeding pair of devices, second means including two resistors andunidirectional current conducting means connecting the cathode of theother of the devices in each of the pairs to the start electrodes in thenext succeeding pair of devices, two control conductors, unidirectionalcurrent conducting means connecting said rst means at a pointintermediate said two resistors to one of said conductors, andunidirectional current conducting means connecting said second means ata point intermediate said two resistors to the other of said conductors.

WILLIAM H. T. HOLDEN.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 2,442,428 Mumma June l, 19482,478,683 Bliss Aug. 9, 1949 2,482,932 Pyatt et al Sept. 27, 19492,489,325 Ridler Nov. 29, 1949 2,502,443 Dunn et al. Apr. 4, 19502,535,303 Lewis Dec. 26, 1950

